.TH "cgeqr2p.f" 3 "Sun May 26 2013" "Version 3.4.1" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME cgeqr2p.f \- .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBcgeqr2p\fP (M, N, A, LDA, TAU, WORK, INFO)" .br .RI "\fI\fBCGEQR2P\fP \fP" .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine cgeqr2p (integerM, integerN, complex, dimension( lda, * )A, integerLDA, complex, dimension( * )TAU, complex, dimension( * )WORK, integerINFO)" .PP \fBCGEQR2P\fP .PP \fBPurpose: \fP .RS 4 .PP .nf CGEQR2P computes a QR factorization of a complex m by n matrix A: A = Q * R. .fi .PP .RE .PP \fBParameters:\fP .RS 4 \fIM\fP .PP .nf M is INTEGER The number of rows of the matrix A. M >= 0. .fi .PP .br \fIN\fP .PP .nf N is INTEGER The number of columns of the matrix A. N >= 0. .fi .PP .br \fIA\fP .PP .nf A is COMPLEX array, dimension (LDA,N) On entry, the m by n matrix A. On exit, the elements on and above the diagonal of the array contain the min(m,n) by n upper trapezoidal matrix R (R is upper triangular if m >= n); the elements below the diagonal, with the array TAU, represent the unitary matrix Q as a product of elementary reflectors (see Further Details). .fi .PP .br \fILDA\fP .PP .nf LDA is INTEGER The leading dimension of the array A. LDA >= max(1,M). .fi .PP .br \fITAU\fP .PP .nf TAU is COMPLEX array, dimension (min(M,N)) The scalar factors of the elementary reflectors (see Further Details). .fi .PP .br \fIWORK\fP .PP .nf WORK is COMPLEX array, dimension (N) .fi .PP .br \fIINFO\fP .PP .nf INFO is INTEGER = 0: successful exit < 0: if INFO = -i, the i-th argument had an illegal value .fi .PP .RE .PP \fBAuthor:\fP .RS 4 Univ\&. of Tennessee .PP Univ\&. of California Berkeley .PP Univ\&. of Colorado Denver .PP NAG Ltd\&. .RE .PP \fBDate:\fP .RS 4 November 2011 .RE .PP \fBFurther Details: \fP .RS 4 .PP .nf The matrix Q is represented as a product of elementary reflectors Q = H(1) H(2) . . . H(k), where k = min(m,n). Each H(i) has the form H(i) = I - tau * v * v**H where tau is a complex scalar, and v is a complex vector with v(1:i-1) = 0 and v(i) = 1; v(i+1:m) is stored on exit in A(i+1:m,i), and tau in TAU(i). .fi .PP .RE .PP .PP Definition at line 122 of file cgeqr2p\&.f\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.